Abstract: A method for treating metal-working fluid comprises reducing a concentration in the metal-working fluid of at least one metal by passing the metal-working fluid through an ion-exchange filter. The at least one metal may comprise cobalt or one or more other metal(s). The ion-exchange filter may include an ion-exchange resin, and the resin may comprise a sulfonated divinyl-benzene-cross-linked polystyrene ion-exchange resin. The metal-working fluid may be recirculated through the ion-exchange filter, from a holding vessel, from a sump or reservoir, or from any other container of the metal-working fluid.

Abstract: An apparatus for treating metal-working fluid comprises: a heating vessel for receiving and holding metal-working fluid for treatment; a heater for heating the metal-working fluid in the heating vessel; an agitator for agitating the metal-working fluid within the heating vessel; an aerator for aerating the metal-working fluid within the heating vessel; and a holding vessel for receiving from the heating vessel and holding treated metal-working fluid. During heating, heated ambient air may be drawn through air inlets and through the fluid agitate and aerate the fluid, thereby ensuring uniform heating and extracting gaseous contaminants. Mist and/or gaseous contaminants may be removed from the airflow prior to its release into the environment. Concentration in the metal-working fluid of at least one metal may be reduced using an using-exchange filter.

Abstract: A method for treating metal-working fluid comprises the steps of: a) transferring the metal-working fluid into a heating vessel; b) heating the metal-working fluid in the heating vessel to maintain the fluid at an elevated temperature during a heating period; c) agitating and aerating the fluid during the heating period; d) transferring the fluid out of the heating vessel into a holding vessel after the heating period; and e) transferring the fluid out of the holding vessel. The fluid may pass through a particle filter before entering the heating vessel, where it may be heated to between about 145° F. and about 210° F. for at least about 30 minutes. During heating, heated ambient air may be drawn through air inlets and through the fluid to agitate and aerate the fluid, thereby ensuring uniform heating and extracting gaseous contaminants. Mist and gaseous contaminants are removed from the airflow prior to its release into the environment.